Public terminals (for example, automated teller machines (ATM) and ticket vending machines) which include touch panels are conventionally known. Moreover, the number of personal use devices (for example, tablet personal computers (PC) and smartphones) using touch panels is increasing.
Touch panels are input devices which detect touches made on the panel as inputs. Touch panels detect touches made by a user on a graphical user interface (GUI) object (a button, for example) displayed in the display region.
A benefit of user interfaces which use this kind of touch panel is that they have high flexibility with regard to positioning of GUI objects. However, user interfaces using this kind of touch panel provide less sensory feedback upon the press of a button compared to user interfaces using conventional, mechanical buttons. This can cause the user to be uncertain about whether a touch he or she made on the touch panel was correctly detected or not.
In light of this, a technique of providing haptic feedback by vibrating the touch panel has been proposed (for example, see Patent Literature 1 (PTL 1)). With the technique disclosed in PTL 1, in order to efficiently vibrate the touch panel, the frequency for vibrating the touch panel is varied based on the position touched on the touch panel (touch position).